Microsoft has now pushed Windows 10 Redstone 4 Preview Build 17074.1002 to insiders in the Slow Ring. The last build for Slow Ring was Build 17025 pushed on November 2 by Microsoft. So, naturally there have been a big number of changes and addition of new features with subsequent preview builds until the Build 17074.1002.
You can read the complete categorized changelog of all Redstone 4 builds so far by clicking here. If you are interested in build-wise coverage, click here to read changelog of the all the builds from Build 17025 to 17074 by clicking here.
Build 17074.1002 also comes with its own set of known issues and fixes and you can read them by clicking here and here.
In case you want to do a clean install of the Build 17074.1002, click here to install 3rd party ISO images